Carbon electrodes for the electrocatalytic synthesis of hydrogen peroxide: A review

Electrocatalytic oxygen reduction by a 2e− pathway enables the instantaneous synthesis of H2O2, a process that is far superior to the conventional anthraquinone process. In recent years, the electrocatalytic synthesis of H2O2 using carbon electrodes has attracted more and more attention because of its excellent catalytic performance and superior stability. The relationship between material modification, wettability and the rate of H2O2 synthesis and service life is considered together with the three-phase interface. The structure of the carbon electrodes and the principles of electrocatalytic H2O2 synthesis are first introduced, and four major catalysts are reviewed, namely, monolithic carbon materials, metal-free catalysts, noble metal catalysts and non-precious metal catalysts. The effects of the metal anode and the electrolyte on the three-phase interface are described. The relationship between carbon electrode wettability and the three-phase interface is described, pointing out that modification focusing on improving the selectivity of the 2e− pathway can also impact electrode wettability. In addition, the relationship between the design of the components in the electrochemical system and their effect on the efficiency of H2O2 synthesis is discussed for carbon electrodes. Finally, we present our analysis of the current problems in the electrocatalytic synthesis of H2O2 for carbon electrodes and future research directions.